Drumm’s Electric Train

This St. Patrick’s Day, lets’ take a look back at a pioneering electric vehicle project, built around a breakthrough battery technology that allowed the nascent Irish government to open a whole new frontier of green transport.

In preparing this entry, the support and contributions of The Irish Railways Records Society have been invaluable, and the stewardship of Steven Matthews TD must also be acknowledged.

The politics of abundant clean energy

The Irish Free State was established in 1922, after a long and bloody struggle to establish independence from the British Empire. However, the Irish Free State was still reliant on the old ruler for many of the daily necessities to function, and chief among these was coal. Coal was used to run factories, drive an extensive rail network, and generate electricity. Ireland had access to a small number of low quality indigenous deposits, whereas Britain was flush with abundant coal sources.

After the establishment of the Irish Free State, an ambitious plan was created to not only generate power sufficient for the entire population of Ireland, but to do so with an indigenous source, and meanwhile create a distribution network to eventually cover the entire population, thereby driving up the standards of living for citizens of the new state. This plan involved harnessing the nations’ largest river, the Shannon, and creating a power supply with ample capacity for demand of the day and further economic growth. As part of this scheme, as well as creating a significant hydro-electric power station at Ardnacrusha in Co. Clare, the scheme encompassed expanding existing lakes to ensure adequate water supply in times of low rainfall. This integration of a buffer of water into the generation plan can be considered as a means of power storage, albeit before the conversion into electrical energy has occurred. Annual electricity demand of the nascent Irish Free State was as low as 16kWh per person in 1926 (and as low as 4kWh in rural settings), a demand which was met fully by the Shannon Scheme. Thus, as the Irish grid was developed to distribute power across the young nation, it was supplied with a transient renewable source (rainfall), buffered through a variety of storage schemes (the major Shannon lakes), before it was converted and dispatched to meet demand. At the time, Ireland had one of the lowest levels of electricity consumption in Europe, ahead of only Portugal.

Ardnacrusha Power Station
Fig. 1: Generators at the Ardnacrusha Power Station – image used under CC Licence

While the country was initially served by Ardnacrusha, the new Electricity Supply Board went on to nationalise some private plants, and so the mix of the grid was partially dependant on fossil fuels from the early 1930s. As demand grew, further hydro plants were added, but the reliance on imported fuel for electricity generation would have significant consequences in the coming decades.

Revolutionary Battery Chemistry

During this intense period of nation-building, in University College Dublin a young research chemist by the name of James Drumm was busily perfecting his PhD proposal for a new type of battery chemistry. In 1929, he applied for a patent on an improved alkaline battery which combined many of the advantages of both alkaline and lead-acid cells. The chief feature of this new chemistry was the high charge and discharge rates achieved, and low internal resistance meant these events could be repeated at high frequency. The construction of the cell from relatively simple materials made it cheap and robust to scale up for industrial purposes. In comparison to contemporaries (notably from the Edison Battery Company) the Drumm battery could charge four times as fast, and discharge up to three times as fast, making strong acceleration and regenerative braking.

Drumm’s first battery, with the inventor standing on the right (image via UCD archives)

The new battery was particularly suited to transport electrification, and Drumm approached the Government for support in creating a prototype train to test the viability of this new battery. The Government of the day were keen to see any proposal which might alleviate the reliance on coal imports while taking up excess electricity capacity, and so the Drumm train was given significant political support. A semi-state company, the Drumm Battery Company, was formed, and £27,000 was made available.

In 1930, a small four-wheeled petrol-driven railcar was modified at the Inchicore rail works, and was outfitted with a 110V battery, as well as 2 22kW motors. This car was tested across the local network, and settled into regular use conveying staff between the Inchicore works and one of the main stations of Dublin (Heuston).

Following this, a dedicated regular service was launched, featuring a train of two carriages and space for 140 passengers, each with it’s own motor and battery setup. The combined railcars weighed 85 tons, including 15 tons of battery, with 450kW of motor power from a 460V setup, made up of 272 cells in series. (For reference, a Telsa Model 3 has 480kg of batteries in a 1730kg vehicle.) The service was inaugurated by President Cosgrave in December 1931, and guests on the service remarked on the incredible acceleration and quiet nature of the electric motors.

A Pathe News clip covering the inaugural run of the Drumm Battery Train

The route served by the train is still in use today, from Dublin Connolly (then Amien Street) to Bray. The route is just under 15 miles, and features a 1 in 48 gradient between Killiney and Dalkey. Recharging the train took 15 minutes, adding roughly 1 mile a minute, and regenerative braking was used during appropriate sections of the journey.

A siding – Regenerative braking in railways

Electrification of railways has been common in many countries throughout the 19th Century, and typically involved a third “live” rail to deliver power, or an overhead wire connected by a pantograph. For such systems, regenerative braking was commonly used to deliver power back into the grid, and would be taken up by any nearby train which needed it. Should this exchange not be possible, then either friction braking or rheostatic braking (dumping power into a dedicated resistor bank, which would be cooled via fans, sometimes called dynamic braking) is employed to compensate. In modern systems, there is a seamless transition between these systems facilitated by microelectronics, and the driver must simply request the desired deceleration rate. But in earlier systems, the friction braking and reverse traction were separate controls, meaning brake blending was really a manual process. The idea of regeneration in on-board systems was even implemented within steam engines, whereby the rheostatic system was water-cooled, and the subsequent steam generated was used to later accelerate the train.

For the Drumm Battery Train, the presence of on-board batteries (or accumulators, to use the contemporary language) meant regenerative braking was constantly available, and as the battery chemistry allowed such significant charge rates, the vast majority of available energy could be converted back to battery charge.

War, the Emergency and the absence of fuel

While the first two trains (A and B) were busily proving their worth through the 1930s, political events at home and abroad were conspiring to amplify the advantages of electric transport. Firstly, an election in Ireland brought a fiercely nationalistic Government to power, who promptly engaged on an economic war with Britain. While Britain placed tariffs on Irish food imports, the Irish tried to decrease fuel imports from Britain, among other things. This policy lasted about 3 years, and the main losers were Irish farmers, who suffered greatly due to lack of market access.

By 1935, the two trains had covered a cumulative 2 million kilometres, and services were increased to in excess of 1500km a week. The economic war lasted a further three years, before a Cattle-Coal Pact was signed by the two governments, effectively normalising relations.

In 1939, a further two Drumm trains were brought into service, making a total of four. A far more significant political episode, the outbreak of World War 2, was to prove these to be timely additions to the Irish rolling stock. While the Irish Free State remained neutral throughout the war, supplies of imported fuel were greatly curtailed, meaning road and rail transport was all but brought to a standstill. During the war period (or the Emergency as it was referred to in Ireland), the Drumm Trains, powered by hydroelectric energy from the Shannon, were relied on very heavily. Dublin’s main coal-fired plant (known as the Pigeon House) was increasingly reliant on deteriorating coal supply.

Hopes for an electric future

While the Emergency was showing the benefits of electrified transport and indigenous renewables, Dr. Drumm himself moved to the US, where he collaborated with Edison on battery research. His work here suggested a 20% improvement in energy density was possible. At the same time, many studies were made into improvements in the design the Drumm Trains (suggesting light weighting as a key next step), and how electrification of the entire network could be adopted, such as by utilising short sections of third “live” rails at suitable intervals, which could allow trains to charge while travelling. Another idea suggested tenders, full of batteries, powering engines, which could be swapped at stations as necessary. These were all assumed to be cheaper and more readily achievable compared to full network electrification. These debates are currently coming full circle in the road transport sector, as cheaper batteries make medium and long distance road haulage a live prospect.

“Events, dear fellow, events”

In 1941, the Irish government decided that global events meant it could no longer support the Drumm Battery Company, and further expenditure on new battery research couldn’t be justified during the Emergency. While the company sought new commercial opportunities to exploit the technology, a lack of raw materials to build samples meant sales activities were effectively stalled during the war period. As no new funding was available, and no sales were forthcoming, the company was effectively liquidated, with only patent fees being paid each year.

And while the battery train could work without direct access to coal, the fact that coal availability determined electricity availability and pricing meant the costs for running the trains were not insulated from fossil fuel availability problems. As shortages became more acute, an unusually dry summer in 1944 meant river levels were a grave concern to Irish electricity capacity.

In 1944, a question in the Irish parliament (the Dail) gave an insight into the electricity consumption of the trains in this period. This suggests 6 to 10 units of electricity for each km of operation, transporting 130 seats. A quick reference to the relevant ESB annual report suggests a unit cost 1.68p, so up to 16.8p per km of train travel, or 0.129p per passenger seat km.

In 1945, a further parliamentary question related to costs for railway transport suggested that the Drumm train was significantly more expensive to operate in comparison to steam equivalents (although the price base for this comparison is difficult to understand, given the extraordinary circumstances in coal markets and declared costs above). This may be explained by differences in maintenance costs, and it is to be assumed that battery maintenance must have warranted a significant extra cost for this comparison to hold water.

Either way, as WW2 came to a close, the Drumm Battery Company was defunct, the inventor had moved to the US, and the Government seemed to have lost its appetite for any further investment in this area. The four trains continued in daily service on the line until the end of the decade, before being decommissioned and eventually scrapped.

While the project may have proven successful in the national context, and provided some much needed public transport during the Emergency, it is noteworthy that political events bookended the trains. Many of the technological ideas of the day are relevant to contemporary transport, and the economics of batteries in heavy duty applications will still be a pressing concern for decades to come.